I used to drive the road from Newcastle to Jozini quite often last year.

The one route I frequently used was through Vryheid, louwsburg, Pongola, Jozini. The road was actually quite decent, with not many potholes, and the like. there was some sections where there was road rutting, but nothing serious. This would most likely be the route you would use to get there from Ladysmith.

I preferred this route as it was the shorter than going through Piet Retief.